For considerable time now absorbent batts have been made from fluffed wood pulp fibers. Such absorbent batts are used in sanitary napkins, disposable diapers, absorbent dressings and the like to produce a media which is highly absorbent and has considerable capacity for holding fluids. The individualized wood pulp fibers are used not only because of their desirable absorbent properties but also because of their softness and low cost. In many instances the batts are wrapped with tissue or nonwoven fabric or the like to prevent linting or dusting of the fibers during use although in certain products the surface of the batt may be stabilized by the addition of a binder to prevent this linting and remove the necessity of using a cover or a wrapping for the batt.
In manufacturing the absorbent, lightweight, fluffy, wood pulp batts a number of problems may be encountered depending on the properties desired in the final batt. For example, a technique for preventing the dusting or linting of fibers is to add a binder to the fibers to stabilize the batt and adhere fibers together. The binders are generally applied from aqueous or other liquid solutions and the addition of liquids to the fluffy batt greatly reduces the loft of the batt. Also, it is extremely difficult to apply the binder uniformly throughout the depth and over the area of the batt. Furthermore, it is very difficult if not impossible to apply certain combinations for reactive materials to the batt such that the reactant product is distributed uniformly. For example, inorganic, insoluble cements such as a calcium silicate made by reacting calcium chloride with sodium silicates cannot be used in these prior processes to stabilize the batt.
I have now discovered a process for manufacturing a highly absorbent, lightweight, fluffy batt of wood pulp fibers which is uniformly stabilized throughout the entire depth of the batt without detrimental effects on the other properties of the batt. My new process does not require the application of liquids or aqueous media to the fluffy batt and hence allows us to maintain the excellent loft of the fluffy batt. Furthermore, my new technique allows the addition of other types of fibers to the wood pulp fibers with relative ease and without detrimental effects on the physical properties of the batt. My new process provides uniform distribution of the stabilizing materials and eliminates problems of migration of these materials in that they are placed in position and stay in that position throughout the process and in the final batt. My new stabilized batts have excellent resiliency, absorbency and bulk and as will be seen from the description given hereinafter my new process has excellent advantages both in economics and in the simplicity of the process.